Previous treatment facilities for phosphating objects require a plurality of work steps, in particular seven work steps, and for this purpose have a plurality of different baths. The object is initially placed in a first bath in which a first liquid for degreasing the object is provided. After the degreasing, the object must be removed from the first bath and conveyed into a second bath. A rinse liquid for rinsing the object is provided in the second bath. After the rinsing, the object is conveyed into a third bath. The third bath is filled with a hydrochloric acid/sulfuric acid mixture. After the hydrochloric acid/sulfuric acid treatment, the object is successively conveyed into two further baths, each filled with a rinse liquid, for rinsing the object. In addition, after the last rinse bath the object is conveyed into a bath for passivation. After the passivation, the object is phosphated and then conveyed to another location for drying. In such a facility, the highly toxic and environmentally harmful chemicals in the degreasing baths and in the treatment baths must be completely replaced after approximately 6 to 8 weeks production time, since after this time the chemicals are depleted, and the sludge that forms must be removed from the baths. This means facility downtime and high replacement and disposal costs.
It is apparent that the facilities known from the prior art on the one hand require a very large amount of space since they must provide six different baths, and on the other hand require a very large number of different chemical substances in large quantities. In addition, conveying the objects from one bath to the next requires a great deal of time, and appropriate transport units and operating personnel. Furthermore, the chemicals used are toxic or environmentally harmful due to the fact that sulfuric acid and hydrochloric acid, for example, are used, as the result of which either costly safety measures must be carried out, or there is high risk to the personnel and the environment as well as the production bay structure, which is usually made of steel.
A further aim is to prevent hydrogen embrittlement of the treated workpieces or treatment objects. Hydrogen embrittlement usually takes place due to the penetration and intercalation of hydrogen in a metal lattice, and may result in material fatigue. Hydrogen embrittlement occurs when, either due to hydrogen corrosion or some other chemical reaction in the metal processing in which hydrogen is involved, atomic hydrogen, which is bound to the material more quickly than it combines to form nondiffusible H2 molecules on the material surface, forms on the metal surface. A portion of the hydrogen is intercalated in the metal lattice, or is deposited at defects or at the grain boundary. Depending on the stress on the particular object, for example due to the introduction of tensile residual stresses and/or tensile load stresses, there is a risk of material failure.